Production of dyeing conversion products of azo-dyestuffs



Patented May 2, 1933 UNITED STATES PATENT o FIcE ERICH WANNER, OF BASED, SWITZERLAND, ASSIGNOR TO THE FIRM J. R. GEIGY S. A., OF BASEL, SWITZERLAND PRODUCTION OF DYEING CONVERSION PRODUCTS OF AZO-DYESTUFFS No Drawing. Application filed. February 13, 1932, Serial No. 592,843, and in Germany February 28, 1931.

This invention is an improvement in or modification of the production of conversion products of azo-dyestufis described 1n the specification of the U. S. Patent No. 1,850,875 dated March 22, 1932. In that specification there is described a process for the manufacture of dyeing products obtained by subjecting a monoazo dyestuff formed by coupling a diazotized amino sulphonic acid compound of the benzene and naphthalene series with resorcin to the action of an oxidizing agent, particularly to air, in presence of ammonia.

According to the present invention this process is conducted in such a way that a monoazo dyestuif formed by coupling a diazotized amino sulphonic acid compound of the benzene and naphthalene series with resorcin is subjected to air as oxidizing agent in presence of ammonia and of heavy metals, such as iron, copper and the like, or compounds thereof, singly or in admlxture.

In this manner, dyeing converslon products are obtained which are still azo dyestuffs, but of which the exact constitution cannot be given. By this treatment, the original dyestuffs which yield mostly yellow to red dyeings become reddishto violet-brown dyestuffs that are no longer capable of dyeing Wool or silk or have only a little dyeing effect thereon, but which have taken an increased dyeing power on leather, the same being dyed in reddishto violet-brown shades of very good fastness to light and alkallne fat liquor. By the additional use of a heavy metal, or a compound thereof, the duration of the conversion is favorably influenced as well as in some cases also the shade of the dyeings of the products.

The following examples illustrate the 1nvention, the parts being by weight Example 1 conversion product thus formed is then isolated by acidification with hydrochloric acid and precipitation with common salt and thereupon freed from. adhering dissolved metlal by washing with diluted hydrochloric aclc.

The new dyestuff dyes leather of somewhat more yellow-brown tints than the dyestuff produced Without the presence of metal, which in its turn requires about 16 hours in order to be thoroughly oxidized. Ifthe heating of the solution and the maintenance of its temperature is performed by means of a steamsupplied sinuous tube of iron, the duration of the reaction further diminishes to about2-3 hours.

The dyestufi produced in this manner, but

Example 2 The azo-dyestuif obtained from 31 parts of diazotized -4-nitro-4-aminodiphenylamine-2-sulphonic acid and 12 parts of resorcin is dissolved in 500 parts of water, which has been rendered distinctly alkaline by means of ammonia, and subjected to oxidation by air at C. for about 20 hours as described in Example 1. Thereupon the conversion product is worked up as hereinbefore described. To heat the solution and to maintain the temperature, steam serpentlnes of iron or copper are used; the tube serving for the introduction of air consists also of one of the said heavy metals.

Without the presence of metal, the complete conversion to the oxidized dyestufl requires at least 40 hours. The same constitutes a dark powder, is easily soluble in water and dyes leather of dark brown tints of excellent fastness to light and alkaline fat liquor. The tints may vary somewhat according to the kind of the used metal.

As azodyestufis to be oxidized in presence of heavy metals there may also be used for example the dyestufi's from sulphanilic acid and resorcin, from L-napht-hylamino-sulphonic acid and resorcin, from 2.3.6-naphthylamino-disulphonic acid and resorcin, from aminoazobenzenedisulphonic acid and resorcin, from 2-nitro-4-aminodiphenylamine-L-sulphonic acid and resorcin, and so What I claim is z 1. A process for the production of dyeing conversion products of azo-dyestufis, consisting in subjecting a monoazo dyestuff formed bycoupling a diazotized amino-sulphonic acid compound of the benzene and naphthalene series with resorcin to. air as oxidizing agent in presence of ammonia and a heavy metal catalyser selected from the group consisting of iron and copper.

2. Aprocess for the production of dyeing conversion products of azo-dyestuifs, consisting in subjecting a monazo dyestuli formed by coupling a diazotized aminosulphonic acid compound of the benzene and naphthalene series with resorcin to air as oxidizing agent in presence of ammonia and copper.

3. A process for the production of dyeing conversion products of azo-dyestufis, consisting in subjecting a monoazo dyestuff formed by coupling a diazotized aminosulphonic acid compound of the benzene and naphthalene series with resorcin to air as oxidizing agent in presence of ammoniaand non.

In witness whereof I have hereunto signed my name this 3rd day of February, 1932.

' ERICH WANNER. 

